the origin and nature of emotions-第18节

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udied　under　these　divisions　were　interrelated。　　Always；　however；　the　conflict　between　votaries　of　these　sciences　has　been　sharp；　and　the　boundary　lines　between　them　have　been　constantly　changing。　Since　the　great　discoveries　of　Darwin；　the　zoologist；　biologist；　and　physiologist　have　joined　hands；　but　still　the　soul…body…spirit　chaos　has　remained。　　The　physician　has　endeavored　to　fight　the　gross　maladies　which　have　been　the　result　of　disordered　conduct；　the　psychologist　has　reasoned　and　experimented　to　find　the　laws　governing　conduct；　and　the　priest　has　endeavored　by　appeals　to　an　unknown　god　to　reform　conduct。

The　great　impulse　to　a　deeper　and　keener　study　of　man's　relation；　not　only　to　man；　but　to　the　whole　animal　creation；　which　was　given　by　Darwin；　has　opened　the　way　to　the　study　of　man　on　a　different　basis。　Psychologists；　physicians；　and　priests　are　now　joining　hands　as　never　before　in　the　great　world…wide　movement　for　the　betterment　of　man。　The　new　science　of　sociology　is　combining　the　functions　of　all　three；　for　priest；　physician；　and　psychologist　have　come　to　see　that　man　is　in　large　measure　the　product　of　his　environment。

My　thesis　to…night；　however；　will　go　beyond　this　common　agreement；　for　I　shall　maintain；　not　that　man　is　in　_*large　measure_　the　product　of　his　environment；　but　that　environment　has　been　the　actual　CREATOR　of　man；　that　the　old　division　between　body；　soul；　and　spirit　is　non…existent；　that　man　is　a　unified　mechanism　responding　in　every　part　to　the　adequate　stimuli　given　it　from　without　by　the　environment　of　the　present　and　from　within　by　the　environment　of　the　past；　the　record　of　which　is　stored　in　part　in　cells　throughout　the　mechanism；　but　especially　in　its　central　batterythe　brain。　I　postulate　further　that　the　human　body　mechanism　is　equipped；　first；　for　such　conflict　with　environment　as　will　tend　to　the　preservation　of　the　individual；　and；　second；　for　the　propagation　of　the　species；　both　of　these　functions　when　most　efficiently　carried　out　tending　to　the　upbuilding　and　perfection　of　the　race。

Through　the　long　ages　of　evolution　the　human　mechanism　has　been　slowly　developed　by　the　constant　changes　and　growth　of　its　parts　which　have　resulted　from　its　continual　adaptation　to　its　environment。　In　some　animals　the　protection　from　too　rough　contact　with　surroundings　was　secured　by　the　development　of　an　outside　armor；　in　others　noxious　secretions　served　the　purposes　of　defense；　but　such　devices　as　these　were　not　suitable　for　the　higher　animals　nor　for　the　diverse　and　important　functions　of　the　human　race。　The　safety　of　the　higher　animals　and　of　man　had　to　be　preserved　by　some　mechanism　by　means　of　which　they　could　become　adapted　to　a　much　wider　and　more　complex　environment；　the　dominance　over　which　alone　gives　them　their　right　to　be　called　〃superior　beings。〃　The　mechanism　by　the　progressive　development　of　which　living　beings　have　been　able　to　react　more　and　more　effectually　to　their　environment　is　the　central　nervous　system；　which　is　seen　in　one　of　its　simplest　forms　in　motor　plants；　such　as　the　sensitive　plant　and　the　Venus　fly…trap；　and　in　its　highest　development　only　in　the　sanest；　healthiest；　happiest；　and　most　useful　men。

The　essential　function　of　the　nervous　system　was　primarily　to　secure　some　form　of　motor　activity；　first　as　a　means　of　securing　food；　and　later　as　a　means　of　escaping　from　enemies　and　to　promote　procreation。　Activities　for　the　preservation　of　the　individual　and　of　the　species　were　and　are　the　only　purposes　for　which　the　body　energy　is　expended。　The　central　nervous　system　hag　accordingly　been　developed　for　the　purpose　of　securing　such　motor　activities　as　will　best　adapt　the　individuals　of　a　species　for　their　self…preservative　conflict　with　environment。

It　is　easy　to　appreciate　that　the　simplest　expressions　of　nerve　response　the　reflexesare　motor　in　character；　but　it　is　difficult　to　understand　how　such　intangible　reactions　as　love；　hate；　poetic　fancy；　or　moral　inhibition　can　be　also　the　result　of　the　adaptation　to　environment　of　a　distinctively　motor　mechanism。　　We　expect；　however；　to　prove　that　so…called　〃psychic〃　states　as　well　as　the　reflexes　are　products　of　adaptation；　that　they　occur　automatically　in　response　to　adequate　stimuli　in　the　environment；　that；　like　the　reflexes；　they　are　expressions　of　motor　activity；　which；　although　intangible　and　unseen；　in　turn　incite　to　activity　the　units　of　the　motor　mechanism　of　the　body；　and　finally；　that　any　〃psychic〃　condition　results　in　a　definite　depletion　of　the　potential　energy　in　the　brain…cells　which　is　proportionate　to　the　muscular　exertion　of　which　it　is　the　representative。

That　this　nerve　mechanism　may　effectively　carry　out　its　twofold　function；　first；　of　self…adaptation　to　meet　adequately　the　increasingly　complicated　stimuli　of　environment；　and　second；　of　adapting　the　motor　mechanism　to　respond　adequately　to　its　demands；　there　have　been　implanted　in　the　body　numerous　nerve　ceptors　some　for　the　transmission　of　stimuli　harmful　to　the　mechanism　nociceptors　some　of　a　beneficial　characterbeneceptors；　and　still　others　more　highly　specialized；　which　partake　of　the　nature　of　both　bene…　and　nociceptorsthe　distance　ceptors；　or　special　senses。

A　convincing　proof　that　environment　has　been　the　creator　of　man　is　seen　in　the　absolute　adaptation　of　the　nociceptors　as　manifested　in　their　specific　response　to　adequate　stimuli；　and　in　their　presence　in　only　those　parts　of　the　body　which　throughout　the　history　of　the　race　have　been　most　exposed　to　harmful　contacts。　We　find　they　are　most　numerous　in　the　face；　the　neck；　the　abdomen；　the　hands；　and　the　feet；　while　in　the　back　they　are　few　in　number；　and　within　the　bony　cavities　they　are　lacking。

Instances　of　the　specific　responses　made　by　the　nociceptors　might　be　multiplied　indefinitely。　　Sneezing；　for　example；　is　a　specific　response　made　by　the　motor　mechanism　to　stimulation　of　nociceptors　in　the　nose；　while　stimulation　of　the　larynx　does　not　produce　a　sneeze；　but　a　cough；　stimulation　of　the　nociceptors　of　the　stomach　does　not　produce　cough；　but　vomiting；　stimulation　of　the　nociceptors　of　the　intestine　does　not　produce　vomiting；　but　increased　peristaltic　action。　There　are　no　nociceptors　misplaced；　none　wasted；　none　that　do　not　make　an　adequate　response　to　adequate　stimulation。

Another　most　significant　proof　that　the　environment　of　the　past　has　been　the　creator　of　the　man　of　to…day　is　seen　in　the　fact　that　man　has　added　to　his　environment　certain　factors　to　which　adaptation　has　not　as　yet　been　made。　　For　example；　heat　is　a　stimulus　which　has　existed　since　the　days　of　prehistoric　man；　while　the　_x_…ray　is　a　discovery　of　to…day；　to　heat；　the　nociceptors　produce　an　adequate　response；　to　the　_x_…ray　there　is　no　response。　There　was　no　weapon　in　the　prehistoric　ages　which　could　move　at　the　speed　of　a　bullet　from　the　modern　rifle；　therefore；　while　slow　penetration　of　the　tissues　produces　great　pain　and　muscular　response；　there　is　no　response　to　the　swiftly　moving　bullet。

The　response　to　contact　stimuli　then　depends　always　on　the　presence　of　nociceptors　in　the　affected　part　of　the　body　and　to　the　type　of　the　contact。　　Powerful　response　is　made　to　crushing　injury　by　environmental　forces；　to　such　injuring　contacts　as　resemble　the　impacts　of　fighting；　to　such　tearing　injuries　as　resemble　those　made　by　teeth　and　claws　（Fig。　9）。　On　the　other　hand；　the　sharp　division　of　tissue　by　cutting　produces　no　adaptive　response；　indeed；　one　might　imagine　that　the　body　could　be　cut　to　pieces　by　a　superlatively　sharp　knife　applied　at　tremendous　speed　without　material　adaptive　response。

These　examples　indicate　how　the　history　of　the　phylogenetic　experiences　of　the　human　race　may　be　learned　by　a　study　of　the　position　and　the　action　of　the　nociceptors；　just　as　truly　as　the　study　of　the　arrangement　and　variations　in　the　strata　of　the　earth's　crust　discloses　to　us　geologic　history。

These　adaptive　responses　to　stimuli　are　the　result　of　the　action　of　the　brain…cells；　which　are　thus　continually　played　upon　by　the　stimuli　of　environment。　　The　energy　stored　in　the　brain…cells　in　turn　activates　the　various　organs　and　parts　of　the　body。　If　the　environmental　impacts　are　repeated　with　such　frequency　that　the　brain…cells　have　no　time　for　restoration　between　them；　the　energy　of　the　cells　becomes　exhausted　and　a　condition　of　shock　results。　Every　action　of　the　body　may　thus　be　analyzed　into　a　stimulation　of　ceptors；　a　consequent　discharge　of　brain…cell　energy；　and　a　final　adaptive　activation　of　the　appropriate　part。　Walking；　running；　and　their　modifications　constitute　an　adaptation　of　wonderful　perfection；　for；　as　Sherrington　has　shown；　the　adaptation　of　locomotion　consists　of　a　series　of　reflexes　ceptors　in　the　joints；　in　the　limb；　and　in　the　foot　being　stimulated　by　variations　in　pressure。

As　we　have　shown；　the　bene…　and　nociceptors　orientate　man　to　all　forms　of　physical　contactthe　former　GUIDE　HIM　TO　the　acquisition　of　food　and　to　sexual　contact；　the　latter　DIRECT　HIM　FROM　contacts　of　a　harmful　nature。　　The　distance　ceptors；　on　the　other　hand；　adapt　man　to　his　distant　environment　by　means　of　communication　through　unseen　forcesethereal　vibrations　produce　sight；　air　waves　produce　sound；　microscopic　particles　of　matter　produce　s